First time the car was left for a while and then it was ok, second time I was pumping the pedal, checking everything, gave up and sarted to drive home on the handbrake. 1/2 mile down the road the brakes came back.

I have no idea whats causing the problem but its not even like the brakes work a little bit, there is nothing there on the pedal what so ever, and then mysteriously its fine again

i'm wondering if the master cylinder seals have gone and need replacing, but I dont understand how they could work intermittently, i thought it would just stop working and that would be that if it was the seals.

They don't always fail completely, so it is possible that it's the seals.

On 16th May, 2012 Simon said:i'm wondering if the master cylinder seals have gone and need replacing, but I dont understand how they could work intermittently, i thought it would just stop working and that would be that if it was the seals.

Just discovered this thread whilst searching for a solution to my own intermittent brake problem. I am 99% sure its the front wheel bearing / loose hub nut, which i would never have worked out in a million years! TM hopefully saves the day again!!

Well its safe to say ive had loose hub nuts for a good 3-4 years, not ideal in a race car! Took the wheels off tonight and the nuts were finger tight..... Torqued them up and the brake pedal feels instantly more assured. The sloppy spongey pedal has gone and the feedback is the same on every dab of the pedal, feels very strange!

Also took the car for a quick test drive and the way it now changes direction feels proper gokart. Cant quite believe its been like this for so long, i just thought all minis were like that!!

Not sure if it will make a huge difference to my times, but with the car being more sure footed and having full confidence in the brakes and their predictability, then heres hoping for a few tenths at least!